Expressions of vascular endothelial growth factor and basic fibroblast growth factor in tumors induced by two different cloned cell lines establishedfrom transplantable rat malignant fibrous histiocytoma

In order to establish base-line data on angiogenic factors in development o f mesenchymal tumors, expressions of vascular endothelial growth factor (VE GF) and basic Fibroblast growth factor (bFGF) in implanted MT-8 and MT-9 tu mors, both derived From a transplantable malignant fibrous histiocytoma (MF H) in the F344 rat, were investigated by immunohistochemistry and Western b lotting method. MT-8 and MT-9 tumors were developed in syngeneic rats by im plant of a tumor tissue fragment. MT-8 tumors were examined on post-implant ation (PI) days 3, 6, 9 and 17, and MT-9 tumors were on PI days 9, 14, 17 a nd 23. The growth of MT-8 tumors was faster than that of MT-9 turners. Hist ologically, MT-8 tumors were features of undifferentiated sarcomas, whereas MT-9 tumors exhibited a typical storiform growth pattern of MFH. Immunohis tochemically, all cells constituting MT-8 and MT-9 tumors reacted with anti bodies to VEGF and bFGF, indicating production of these Factors by mesenchy mal neoplastic cells. However, there were no marked differences in these im munoreactions between turners examined. Thus, the bands obtained in the Wes tern blotting methods were densitometrically scanned. The expression levels of VEGF and bFGF gradually increased PI day 3 to 9 in MT-8 tumors and PI d ay 9 to 17 in MT-9 tumors. On last examination day, the levels of bFGF in b oth tumors and of VEGF in MT-9 tumors decreased, but the VEGF expression le vel in MT-8 turners was still increased. Tnt se findings indicated that VEG F and bFGF may contribute cooperatively to angiogenesis in an early growth of mesenchymal turner development.